This invention relates to devices for cleaning ink from the orifice plates in ink jet systems and, more particularly, to a new and improved cleaning device for an ink jet orifice plate in a hot melt ink jet system.
In ink jet systems, the orifice plate from which ink drops are ejected tends to accumulate a quantity of ink because of accidents during operation, spattering of ink as a result of tails or satellites in the ink drops, and purging of air from the ink supply lines. In hot melt ink systems, the ink jet head is held at a high temperature so that the ink which accumulates on the orifice plate remains liquid during operation of the system. Consequently, drops may be released from the surface of the orifice plate during printing and deposited on the print medium, producing a defective print, or into the mechanism, causing reliability problems.
Heretofore, wiper blades have proposed for scraping molten hot melt ink from the surface of an orifice plate in a hot melt ink jet system, but once the ink has been removed, it solidifies on the wiper blade, presenting difficulty when the blade is to be used again. Other cleaning systems using replaceable ink-receiving media such as paper or cloth have been proposed or used. In one case, for example, a D-shaped roller made of resilient material is normally oriented with its flat surface facing the printhead so as to avoid contact with the orifice plate. When cleaning is required, a cloth web held against the D-shaped roll is advanced, causing the roll to rotate so that the web is pressed against the orifice plate during three-quarters of the rotation of the roll. In that case, the pressure applied to the orifice plate varies depending on the compliance of the resilient material of which the roll is made and the tension in the cleaning web, causing variations in the pressure and permitting relatively high pressures to be applied to the orifice plate which can result in abrasive deterioration of the plate.